Pharm Test 3

Question 1

Distribution depends on: 5 things

Answer 1

BF, capillary permeability, protein binding, lipophilicity, tissue volume

Question 2

Plasma Compartment

Answer 2

(intravascular fluid), low Vd, 4% water weight, high mol weight drugs

Question 3

Extracellular Compartment

Answer 3

(interstitial and plasma), high Vd, 20% water weight, low mol weight drugs

Question 4

Volume of Distribution (eq)

Answer 4

Vd= dose [ ] / plasma drug [ ] (or total fluid drug [ ])

Question 5

Half life determines

Answer 5

dose frequency, elimination, length of effect

Question 6

Clearance (eq)

Answer 6

CL= (.639 x Vd)/half life

Question 7

First Order Kinetics

Answer 7

constant proportion

- rate of drug elimination is proportional to drug [ ]

Question 8

Zero Order Kinetics

Answer 8

constant rate

-rate of elimination is independent to drug [ ]

Question 9

Biotranformations Phases 1 and 2

Answer 9

• Goal is to become hydrophilic for excretion
  phase 1= adds polarized group (hydrolysis, oxidation by CYP 450 enzyme)
  phase 2= links to acid= inactive (conjugation)

Question 10

Urine Excreion=

Answer 10

filtration + secretion - reabsorption

Question 11

Steady State proportional to? and inversely to?

Answer 11

• infusion

- clearance

Question 12

Loading Dose (eq)

Answer 12

LD= Vd x Css (mg)

Question 13

Maintenance Dose (eq)

Answer 13

MD= CL x Css (mg/kg/hr)

Question 14

Drug Approval Process (4 steps)

Answer 14

in vitro, animal testing, clinical testing, marketing

Question 15

Clinical Trials (4 phases)

Answer 15

• phase 1= small population, evaluate dose response
• phase 2= evaluates efficacy, larger group, placebo, blind
• phase 3= lots of population, comparison with other drugs, evaluate effects, placebo, blind
• phase 4= post marketing surveillance, toxicity

Question 16

Drug must have appropriate

Answer 16

size, electrical charge, shape, atomic composition

Question 17

Drug Electrical Charge (receptor bonds) - 3

Answer 17

• covalent= irreversible
• electrostatic= pos attract to neg
• hydrophobic= weak (more selective)

Question 18

Major Receptor Families

Answer 18

• ligand gated ion channels (sec)
• g protein/cascade (min)
• enzyme linked receptors: activates enzyme (hours)
• intracellular receptors (days)= makes protein

Question 19

Spare Receptors

Answer 19

only a fraction of total receptors needed to elicit max response

Question 20

Protection from Excess Stimulation (3)

Answer 20

• desensitization
• down regulation
• refractory period

Question 21

Potency vs Efficacy

Answer 21

P= amount of drug needed to produce given percent effect
E= magnitude of response a drug causes

Question 22

EC50

Answer 22

concentration producing 50% of max effect (potency)

Question 23

4 Laws of Drug Receptor

Answer 23

1- drug and receptor combine reversibly
2- occupied receptors proportional to # of drug and receptors
3- magnitude proportional to activated receptors
4- plateau effect because of limited # of receptors

Question 24

Agonist

Answer 24

Binds to receptor and makes response
1- full agonist- produce Emax
2- partial agonist- can’t produce Emax
3- inverse agonist- stabilized inactive form

Question 25

Antagonist

Answer 25

blocks response
1- competitive- enough agonist can overcome it (high potency)
2- noncompetitive- cannot be overcome by agonist (lower Emax)
a- irreversible- covalent bond can’t come off
b- allosteric- binds to different site and blocks activation
3- functional- different receptor and opposite effect
4- chemical- drug binds to agonist

Question 26

Quantal Dose-Response (ED50 and TD50)

Answer 26

measure safety

• ED50- dose for therapeutic effect in 50% population
• TD50- dose for toxic effect in 50% population

Question 27

Therapeutic Index (eq)

Answer 27

TI= (TD50)/(ED50)

needs to be above 2